“It’s easy to talk!” roared Rogers.  “If one of these big ’uns gets us broadside on, our number’s up!"...

“Cutter putting over for Sheppey coast, sir!” bellowed the man in the bows.

Stringer raised himself, weakly, and sought to peer through the driving spray and rain-mist.

“By God!  They’ve turned—­Turtle!"...

“Stand by with belts!” bellowed Rogers.

Rapidly life belts were unlashed; and, ahead, to port, to starboard, brine-stung eyes glared out from the reeling craft.  Gray in the nascent dawn stretched the tossing sea about them; and lonely they rode upon its billows.

“Port!  Port!  Hard A-port!” screamed the lookout.

But Rogers, grimly watching the oncoming billows, knew that to essay the maneuver at that moment meant swamping the cutter.  Straight ahead they drove.  A wave, higher than any they yet had had to ride, came boiling down upon them... and twisting, writhing, upcasting imploring arms to the elements—­the implacable elements—­a girl, a dark girl, entwined, imprisoned in silken garments, swept upon its crest!

Out shot a cork belt into the boiling sea... and fell beyond her reach.  She was swept past the cutter.  A second belt was hurled from the stern...

The Eurasian, uttering a wailing cry like that of a seabird, strove to grasp it...

Close beside her, out of the wave, uprose a yellow hand, grasping—­seeking—­clutching.  It fastened itself into the meshes of her floating hair...

“Here goes!” roared Rogers.

They plunged down into an oily trough; they turned; a second wave grew up above them, threateningly, built its terrible wall higher and higher over their side.  Round they swung, and round, and round...

Down swept the eager wave... down—­down—­down...  It lapped over the stern of the cutter; the tiny craft staggered, and paused, tremulous—­dragged back by that iron grip of old Neptune—­then leaped on—­away—­headed back into the Thames estuary, triumphant.

“God’s mercy!” whispered Stringer—­“that was touch-and-go!”

No living thing moved upon the waters.

XLI

WESTMINSTER—­MIDNIGHT

Detective-Sergeant Sowerby reported himself in Inspector Dunbar’s room at New Scotland Yard.

“I have completed my inquiries in Wharf-end Lane,” he said; and pulling out his bulging pocketbook, he consulted it gravely.

Inspector Dunbar looked up.

“Anything important?” he asked.

“We cannot trace the makers of the sanitary fittings, and so forth, but they are all of American pattern.  There’s nothing in the nature of a trademark to be found from end to end of the place; even the iron sluice-gate at the bottom of the brick tunnel has had the makers’ name chipped off, apparently with a cold chisel.  So you see they were prepared for all emergencies!”